Plastic Double Bagging

May 30, 2011 5:41 PM

Help settle an argument about plastic bags.

We save all our plastic grocery bags and reuse them as trash can liners. I often find bags which have holes in them, so I double-bag with those, and I always put the bag with the hole into the bag with no hole, rather than the other way around. My wife insists that it doesn't matter if the bag with the hole is on the inside or the outside as it's only one layer of plastic either way. I think by putting the bag with the hole into the other bag it's stronger than if the hole was on the outer bag, but I honestly have no proof of this.

So, who's right? Is it stronger to have the bag with the hole inside the bag with no holes, or the other way around, or is there no difference?

posted by mr_crash_davis to Grab Bag (17 answers total)

I can't see one way being much better than the other, unless your garbage is pretty heavy, in which case I'd probably put the hole-free bag on the outside.
posted by futureisunwritten at 5:45 PM on May 30, 2011

Having done this "experiment" while carrying loads of books, I can say with confidence that you are right. And both configurations are stronger than just one hole-free bag. However, unless your garbage consists of bricks, I can't see that an amount of trash small enough to fit in a shopping bag would be heavy enough for your bag order to matter.
posted by phunniemee at 5:51 PM on May 30, 2011 [1 favorite]

Do you tie both bags when closing it, or just the outer one? If the inner one is left loose, then the plastic won't be under as much tension and therefore probably won't rip more. (I put the busted one on the inside too, but I've never actually thought it through. I just usually don't find the hole until something's already inside it, so I just drop the whole thing into another bag.)
posted by restless_nomad at 5:51 PM on May 30, 2011

I put the holey bag on the outside, but I have no idea why I do this or if it's right. But if my wife asked me to do it the other way, I'd do that, since I don't really care either way, and it's definitely not a hill to die on (I am also agnostic about which way the toilet paper goes, so I might be a freak).
posted by rtha at 5:52 PM on May 30, 2011 [2 favorites]

If you're worried about something catching on the hole and enlarging it, it's stronger if the bag with the hole is on the outside.

If you're worried about something poking through the bags, it doesn't matter - if there's something that can poke through one bag and not two together, if it finds the hole, or the spot of inside-bag-over-the-hole, it'll poke through.

If you're worried about things (especially liquids) falling out and through the hole, it's better to have the intact bag on the inside. If the bag with the hole is on the inside, things will find their way through to the second bag no matter how careful you are, and then the question's moot.
posted by WasabiFlux at 5:54 PM on May 30, 2011

Assuming there are liquids involved, it's better to have the bag with the holes on the outside, because it acts as outside protection and support for the inner bag, which contains the liquids. If this is reversed, then liquids spread to the outer layer immediately, and if later punctured in the trash can, this would allow the liquids to escape, while the other bad would resist the puncture better.
posted by Brian B. at 5:57 PM on May 30, 2011 [13 favorites]

I say you're right. The weakest part of the bag is the hole. Any deformation due to stress will occur around it. Think of force spreading the hole open in an outward direction. If the hole is contained by the second bag, this outward spreading cannot occur, because the second bag acts as a barrier to the expansion of the first. But if the situation is reversed, with the hole on the outside, the first bag can (given the right set of pressures) act like a wedge in the hole to open it.

But this is an incredibly stupid argument and the difference is probably negligible.
posted by dephlogisticated at 6:06 PM on May 30, 2011 [2 favorites]

The bag with the hole in it is good for recycleable trash and the continent bag for wet garbage.
posted by effluvia at 6:09 PM on May 30, 2011 [1 favorite]

Look at it like this: a plastic grocery bag with a hole in it is effectively "trash", and thus it goes into the plastic grocery bag without the hole in it, which is the "trash bag". When was the last time you took a perfectly good, hole-less plastic grocery bag and tried to use it like the Katamari Damacy dude and rolled it around in a bunch of orange peels and empty meat packets and used band-aids and hoped they would stick to it and that would become your "trash-ball" with the perfectly good trash bag as the seed, or "marrow"? My guess is you've never done that. Therefore you are correct: trash goes into the trash bag. One does not wrap trash around the trash bag.
posted by tumid dahlia at 6:16 PM on May 30, 2011 [4 favorites]

I'm with Brian B. as well - the holey bag is a safeguard if the unholey bag gets punctured.

If the garbage is dry, similar thing applies; if the inner unholey bag is ruptured, the outer holey bag is backup/maintains structural integrity.

However, spacewrench is the most correct.
posted by porpoise at 6:23 PM on May 30, 2011

So wait - if you have a bag without a hole, you don't double bag it, you just use it single - is that right? And it works just fine as a single?

Then why in the world would you double bag with a holey bag anyway? Couldn't you just use the non-holey bag as the liner like you always do, and crumple up the holey bag with the rest of the trash?
posted by CathyG at 7:32 PM on May 30, 2011

And do you also discuss how to put the toilet paper roll on the holder? I'd recycle the bags with holes in them and re-use the other ones.
posted by Ideefixe at 7:47 PM on May 30, 2011

I'm with CathyG, this is a waste of an unholey bag. The answer is to double-bag with two holey bags that have holes in different spots.
posted by freejinn at 8:01 PM on May 30, 2011

No, because then the liquid leaks out of the corner of the first, or "inner", bag, then hits terminal velocity by the time it leaks out the opposing corner of the second, or "outer", bag, and before you know it you're firing all sorts of gunk around. Diseased sponge water, rancid albumen, old milk that's gone all chunky, just squirting the walls of the kitchen like a sick hose.
posted by tumid dahlia at 9:03 PM on May 30, 2011

I don't know about strength but it feels somehow wrong to have a broken bag on the outside. Broken things go inside things that aren't broken.

And do you also discuss how to put the toilet paper roll on the holder?
Heh.
posted by unliteral at 10:13 PM on May 30, 2011

Neither. Use the bag without the hole for your garbage. Put the bag with the hole in the recycle/soft recycle bin since it's waste.
posted by Ookseer at 11:56 PM on May 30, 2011

If you're ok with single bagging it, we just tape over small holes.
posted by advicepig at 8:42 AM on May 31, 2011